Polycyclolihales
Diagnosis
Calcareous nannofossils consist of a double-storey wall, each containing three to twenty-four radiating segments. The two walls may or may not be joined by a central diaphragm.
Description
Optical Properties: In the plan view, Polycyclolithaceae exhibit inclined extinction with length-slow (+) elongation (Figures 18A–B, 17I–J in Varol, 2025a). In the side view, they also exhibit inclined extinction but with length-fast (−) elongation (Figures 18F, 18N in Varol, 2025a).
References
Varol, O. 2025a. A practical guide to optical studies of calcareous nannofossils. Grzybowski Foundation Special Publication. 29: 1-222
